Polyimides, in particular polyetherimides (PEI) are amorphous, transparent, high performance polymers having a glass transition temperature (Tg) of greater than 180° C. Polyetherimides further have high strength, toughness, heat resistance, and modulus, and broad chemical resistance, and so are widely used in industries as diverse as automotive, telecommunication, aerospace, electrical/electronics, transportation, and healthcare. Polyetherimides have shown versatility in various manufacturing processes, proving amenable to techniques including injection molding, extrusion, and thermoforming, to prepare various articles.
However, they are typically high viscosity materials and the high viscosity, combined with the high Tg, can hinder the use of polyetherimides in certain manufacturing operations, such as the manufacture of composites and coatings. For example, because of the high Tg of polyimides, formation of intricate parts or highly conformal coatings requires high temperatures that may not be compatible with other components. Composites, coatings, and thin films are currently manufactured using polymer solutions containing organic solvents, which adds removal and recycling costs. Residual solvent can be a further issue in certain applications, particularly the electronics industry.
There accordingly still remains a continuing need for new methods of manufacturing polyetherimides and articles comprising the polyetherimides, particularly methods that do not rely on organic solvents.